What Is Bid-Ask Spread?
The bid-ask spread is the difference between the highest price a buyer will pay and the lowest price a seller will accept. Learn how spreads affect your trades.
Definition
The bid-ask spread is the difference between two prices: the bid (the highest price a buyer is willing to pay) and the ask (the lowest price a seller is willing to accept). If a stock has a bid of $49.95 and an ask of $50.05, the spread is $0.10. This spread is essentially the cost of doing business -- it is the profit that market makers earn for facilitating trades.
Liquid stocks like Apple or Amazon have tiny spreads, often just a penny. Thinly traded stocks, penny stocks, and options can have spreads of 5-10% or more of the stock price. The spread is a hidden transaction cost: you buy at the ask and sell at the bid, so you start every trade slightly underwater.
Spreads widen during periods of high volatility or uncertainty, such as earnings announcements or market crashes. They also tend to be wider during pre-market and after-hours trading when fewer participants are active. Understanding the spread helps you understand the true cost of entering and exiting positions.
Real-World Example
A stock shows a bid of $24.90 and an ask of $25.10 -- a spread of $0.20. If you place a market buy order, you pay $25.10. If you immediately turn around and sell at market, you get $24.90. You just lost $0.20 per share (0.8%) without the stock moving at all. For a large-cap stock with a $0.01 spread, that cost is negligible. For a penny stock with a $0.10 spread on a $1.00 stock, you lose 10% just getting in and out.
Why It Matters
The bid-ask spread is the invisible tax on every trade you make. For buy-and-hold investors purchasing liquid stocks, it is trivial. For active traders making dozens of trades per day, or anyone trading illiquid securities, the spread can eat into returns significantly. Checking the spread before placing a trade is a basic habit that separates informed investors from beginners. If the spread is wide, use a limit order to avoid paying the full ask price.
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Frequently Asked Questions
What is a tight vs wide bid-ask spread?
A tight spread (a few cents) indicates high liquidity and lots of trading activity. A wide spread (many cents or even dollars) indicates low liquidity, fewer participants, or higher uncertainty. Always prefer stocks with tight spreads.
Who profits from the bid-ask spread?
Market makers -- firms that continuously post buy and sell orders -- earn the spread as compensation for providing liquidity. They buy at the bid and sell at the ask, pocketing the difference on each trade.
How can I reduce the impact of the spread?
Use limit orders instead of market orders. Trade liquid stocks with tight spreads. Avoid trading during pre-market, after-hours, or high-volatility periods. These practices minimize the spread cost.
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